1. Field of the Invention
The Invention relates to aircraft landing gear and, more specifically to an integrated wheel hub motor/generator, regenerative braking and/or motorized braking method for an aircraft landing gear system, which reduces wear of the braking system and the associated tires while improving stability of said aircraft and reducing the need for maintenance due to wear.
2. Related Art
It is known in the field of aircraft wheel and brake assemblies to provide a non-rotatable wheel support, a wheel mounted to the wheel support for rotation, and a brake disk stack using friction braking to convert rotary motion of said disks into friction heat energy which creates wear of said disks. Various brake actuation configurations and methods are known, as in U.S. Pat. Nos. 4,381,049, 4,432,440, 4,542,809, 4,567,967, 4,596,316, 4,865,162 and 6,615,958.
The current state of the art for providing braking systems for aircraft uses stators and rotors, which are forced into physical contact with each other thus generating friction heat that introduces wear of the associated disks and requires periodic maintenance to replace the worn parts.
The primary drawback of carbon disk brakes of the latest designs is that a greater volume of carbon material is needed to absorb the same amount of heat energy as that of steel disk brakes. Another drawback of carbon disk brakes is the diminished braking capacity due to moisture contamination of the carbon surfaces due to rain and the high replacement cost after they are worn.
Furthermore, aircraft are required to maneuver within the defined taxies, runways and terminals. One such requirement is the 180-degree turn that places an upper limit on the aircraft allowed for a particular runway based upon the width of the runway and the ability of said aircraft in conducting a 180-degree turn there on within the physical width of said runway. Current landing gear provides limited abilities to perform such 180-degree turns.
One significant concern in aircraft brake design is the dissipation of kinetic energy of aircraft within the braking system of the landing gear system during landing and rejected takeoff conditions. Ultimately, it is the rolling friction present between the tires and the landing surface, which slows the aircraft, thus brake capacity requirements are based upon maximum landing weight of the aircraft and the rolling friction. Braking systems of the prior art are relatively inflexible with respect to the manner in which they generate the required braking force.